All Penguin Bio-Weel Power Filters deliver easy, three-stage mechanical, chemical and biological aquarium filtration. Convenient Penguin Rite-Size Filter Cartridges come ready to use with each filter. Ready to mechanically and chemically remove waste, discoloration and odors. Each contains new faster-actiong Black Diamond Premioum Activated Carbon for maximum efficiency. Biological filtration is provided by the revolutionary and patented Bio-Wheel - proven best at removing toxic ammonia and nitrite. All Bio-Wheel filters feature noise-reducing two-piece vented covers & adjustable mid-level intake strainers. This unit uses the Rite Size B filter cartridge.